You forgot about the vital dark resist in which the majority are physical attacks. Plus those calcs were just put there to demonstrate the difference in their bulk. And what makes Landorus-T take brave birds any better than Krook?
Well, I will be honest in that I have yet to see anyone use physically defensive Krookodile in this meta (I saw specially defensive, which is worse, but I digess). The problem is that standard Landorus-T and standard Krookodile are only similar in typing and ability, and nothing else. Krookodile doesn't even run Intimidate all the time, as Moxie makes him a good late game sweeper. But either way, standard Landorus-T does take physical hits better than Krookodile. I think most people would agree that Landorus-T doesn't need a lot of speed, except in cases where you need to speed creep.
Actually, I looked this up, so I admit my ignorance. Impish/Adamant HP/Def spreads make up ~43% of Krookodiles (in the 1760 stats).
For Landorus-T, most people run Jolly 252HP/252Def, which is not my thing, but whatever.
What I said about Talonflame was under the assumption that most Krookodiles wouldn't be defensive. And about 30 to 40% of them still are offensive sets.
Furthermore, I don't think a dark resist is very good on a Pokemon with intimidate when the primary dark-type Pokemon in the tier gets a net +1 attack buff from it. Weakness to fairy is also unfortunate, although all the fairies in the tier (perhaps except Togekiss, who only checks) can take him on fairly easily. Also 180+ Bisharp outspeeds uninvested Krookodile (I'd rather run Adamant, but Jolly still exists) and 2HKO's it, so not a very sharp counter, more of a decent check. Also, depending on the HP investment of said Bisharp, Krookodile can fail on OHKOing Bisharp with Earthquake.
As for other matchups, like with Mandibuzz, I'm not really sure what Krookodile can do back to it -- so Mandibuzz can easily stall it out. It does make a good DD Tyranitar counter though, something I hadn't thought of before, although like most physical walls, it falls to Tyranitars with Ice Beam (12%, so probably not a huge deal).
== Calcs ==
+1 252 Atk Life Orb Bisharp Iron Head vs. 252 HP / 252+ Def Krookodile: 207-243 (52.5 - 61.6%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
0 Atk Krookodile Earthquake vs. 32 HP / 0 Def Bisharp: 248-294 (88.8 - 105.3%) -- 31.3% chance to OHKO
0 Atk Krookodile Earthquake vs. 0 HP / 0 Def Bisharp: 248-294 (91.5 - 108.4%) -- 50% chance to OHKO
0 Atk Krookodile Earthquake vs. 252 HP / 0 Def Bisharp: 248-294 (74.2 - 88%) -- guaranteed 2HKO
0 Atk Krookodile Stone Edge vs. 252 HP / 252+ Def Mandibuzz: 114-136 (26.8 - 32%) -- 43.8% chance to 4HKO after Leftovers recovery4
88+ SpA Tyranitar Ice Beam vs. 252 HP / 0 SpD Krookodile: 200-236 (50.7 - 59.8%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery